I know you haven't seen all of the trailers and whatnot you've been wanting to see. The best versions of the trailers are the ones from Apple, but if you're having trouble with viewing them on your old P.O.S. PC, I've also included the official sites which have different versions of the files. I'm posting them here in case anybody else reading this is interested:
Harry Potter and the Goblet of Fire Quicktime and Official Website
Serenity Quicktime and Official Website
Harry Potter and the Goblet of Fire Quicktime and Official Website
Serenity Quicktime and Official Website